Has anyone seen a device like this? I was told its most likely German but who knows, Likely something missing.

Here is what I have observed so far.

Periscope looks straight up so likely some kind of rangefinder etc. missing from the top.

Stock holsters comfortably aiming periscope straight up but also straight forward, that however leaves the business end pointing down so likely not.

Trigger operates a release lever on front of barrel tube thingie.

There is a second spring loaded lever at the front of the barrel tube, it is in open position and nothing actuates it.

There also looks like there is some kind of center firing pin in the bottom of barrel but also nothing seems to actuate it.

The knob on bottom likely operates angel of periscope (moves top in and out from stock)

My next step is to disassemble this thing to see if there are any markings on inside and to free the periscope knob it thatch what it is, Im not sure if all the parts will survive the disassembly so all information before that happens is greatly appreciated.